Jump to content

115 mbp/s??? CANON DSLR


Recommended Posts

  • Replies 55
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Matt, The programmer 1% posted some videos. Night time and raining - Lamp shining on a brick wall. 4 videos (gop1/3/6/12) I looked at 2 of the 4 videos (gop1 and gop3). The gop3 video setting looks

[quote name='P4INKiller' timestamp='1347567267' post='17921'] I'm using a 64GB 95MB/s sandisk card, and I can't go above CBR 1.4. I don't see these noise improvements people keep mentioning. I re

[quote name='jgharding' timestamp='1347573091' post='17934'] It is ;) You have to switch off sound recording in the normal Canon menus, then you can get to 2.8 or 2.9 with that card. [/quote


You'll like this. 1% added this today.

[b][i]In daylight it still works, ramp down is good, ramp up is a little too fast I think. 1 second polling for BR and buffer is a little too slow, would like .5 seconds. Bit rate is a little bit jaggy (follows card write) but better quantizer used overall than CBR function or VBR function and mostly stops overruns unless they happen really suddenly or scene is already too big to encode. I set buffer warning to like 50/60% and had success at ISO 80-2500.

[color=#FF0000][u]Low points of BR are usually above default rate of 40.[/u][/color] Footage is overall 1GB per minute. A 7minute continues shot was ~7GB. [color=#FF0000][u]Average BR is over 120, peaks 160-200.[/u][/color] The drop downs aren't really noticeable in watching, I have to see if they show up in post but I doubt they will as BR at worst quantizer is still usually very high. [/i][/b]
Link to post
Share on other sites
Sounds interesting. Perhaps too hopeful or not?

1% programmer:

[i]600D already does ALL-I 176mbps.. I've gotten past 200 for short periods. I'm actually trying to slow it down at this point. Card sustained is only 160. T4i will probably do like 400mbps in UHS-1. 2k and 4:2:2 can probably happen if we get at what's being fed to the encoder.[/i]
Link to post
Share on other sites
Latest from 1% programmer. A very interesting read...

[b]Quote[/b][indent][b]because there is no interframe dependence[/b][/indent]

[b][i]Yep, I frame dropped from buffer almost immediately. P frame sticks around for a while while its doing more passes, etc.

The P frames are only a little bit more compressed and really the main reason to use them is file size/buffer. 1GB a minute is hardcore no matter how you do it. Also, no B frames yet... Gop3 is where its closer to old file sizes and doesn't write almost all the time. I think the I frame has to be like 10-15% bigger for the same quality so instead of a decent 130mbps you end up at 160-170mbps and you actually do crash if the encoder slows down or the card does. Should test gop of 2,3-6... any more than that and too much is held in the buffer.

Qscale drops like a stone when the buffer warning comes on but it ramps up right away with the faster polling. You can turn on debugging and watch it. Qscale with canon functions only moved by one. With slice you can go from 128 to 87 instantly. [color=#FF0000]I think canon was really going for consumers and smaller files rather than quality. They want you to buy a more expensive camera rather than using a 600D, etc. [/color]The weird thing is that they don't like offering swappable lenses on their camcorder offerings. Heavy grading will really show if the bit rate dips matter or not. If a few frames get all funky out of a whole sequence then we'll know.

Other cameras:

50D = Did not change gop.
550D = no breaking 4gb limit so you'll have all of 4 minutes of footage.
60D = untested for both limit and gop.
T3 = can probably pull it off
5d3 = different encoder, different hacks
5d2 = don't have one and nobody has really looked in on it. Encoder also slightly different. CF cards should in theory do more than 20MB/s write. A1ex has one so he'd be the guy to try it. But still have to hack the 4gb limit and 5d2 is the same generation as 550D so maybe only 32bit value for file size [img]http://www.magiclantern.fm/forum/Smileys/default/sad.gif[/img]

What's left?

MJPEG might end up giving better results and actual full frame video, none of this 1600x960 crap. Although maybe native recording and resizing later might give better results for regular H.264 than in camera resized 1920x1080. [color=#FF0000][size=6][u]I can continually take shots at S1 which is like 2592x1728 so 2k video seems possible. [/u][/size]Ma[/color]x file size per frame would be like .83MB to get 24p out of that. .67 for 30P... not a whole lot of room. SD interface max speed at 48mhz is 25MB but no card seems to want to keep up. How good can you get at that data rate?

Line skip is likely so it can fit the entire frame into reduced resolution without resizing the whole image and taking up CPU time, etc. It IS controllable since 600D has 1:1 crop and even zooming. But the issue will be that the frames are bigger and more complex to encode.. hence static and trees are very evil.

Right now, encoder in the hand is worth 2 in the theoretical stage. [/i][/b]
Link to post
Share on other sites
[quote name='jgharding' timestamp='1347377497' post='17776']It's a bit of a lost cause, when the 550D and 600D have much better image quality through ML2.3, and 7D support hasn't even begun.[/quote]I thought that the image quality of all the Canon APS-C sensor DSLRs was the same. They are using the same sensor after all & Magic Lantern is more about improving functionality than anything else (unlike the GH2 hack which doesn't alter functionality at all).
Link to post
Share on other sites
Hey everyone,

Andy600 from Magic Lantern had two 3 second clips put up for a quick look via download. He was testing the higher bitrates. I downloaded his clips and color graded one of them. It is posted below. Note: The clip he had for download was compressed, so I was working with compressed footage. It was very robust to grade even though it wasn't the original. Forgive me for my color grading as I use a tv as a monitor. His camera was the Canon 600D.

Link to post
Share on other sites
[quote name='nigelbb' timestamp='1347387943' post='17781']
I thought that the image quality of all the Canon APS-C sensor DSLRs was the same. They are using the same sensor after all & Magic Lantern is more about improving functionality than anything else (unlike the GH2 hack which doesn't alter functionality at all).

It is, without the hack applied.

Magic Lantern is a much deeper hack now. They've improved the noise level of all the ISO settings, as well as highlight roll-off for certain settings. The 7D is locked to the default bitrate (48mbps I think), while ML2.3 equipped 550D for example, will peak at 120 or so in high ISO high-complexity scenes if you use a fast card, it's far nicer as the noise is easier to remove, it isn't mushed into the image. The higher bitrate footage has more detail and grades a little more subtly.

They're also close to cracking All-I 160mbps for 550D, 600D etc. So it really is a hack not only for amazing still and video functionality, but also improving the bitrates of the camera. The release versions are also incredibly stable.

My biggest bug-bear with the 7D lack of ML though, beside the lower bitrate, is no live histogram or peaking, I don't think I could do without those now!

It is waterproof though.
Link to post
Share on other sites
There is a chance that it will be opened up to ML, but a few have tried and failed. It seems the different hardware (two processors) and the like are stopping them from exploiting the camera running code on it. At this stage most people appear to be working on the more popular XXXD models, or the newer 5D iii, so I think the smart bet would be to write off ML on 7D.
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...